#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

char *menu[] = {
    "a - add new record",
    "d -delete record",
    "q -quit",
    NULL,
};

int getchoice(char *greet,char *choices[]);

int main(){
    int choice = 0;

    if (!isatty(fileno(stdout))){ //isatty标准输出是否已连接到一个终端，如果没有退出程序 
        fprintf(stderr,"You are not a terminal!\n");
        exit(1);
    }
    
    do {
        choice = getchoice("Please select an action",menu);
        printf("You have chosen:%c\n",choice);
    }while (choice != 'q');
    exit(0);
}

int getchoice(char *greet, char *choices[]){
    int chosen = 0;
    int selected;
    char **option;

    do {
        printf("Choice:%s\n",greet);
        option = choices;
        while (*option){
            printf("%s\n",*option);
            option++;
        }
        selected = getchar();
        option = choices;
        while (*option){
            if (selected == *option[0]){
                chosen = 1;
                break;
            }
            option++;
        }
        if (!chosen){
            printf("Incorrect choice,select again\n");
        }
    }while (selected == '\n');
    return selected;
}